By A.J. Bailey, Colorado Master GardenerSM, Colorado State University
Cooperative Extension, Denver County

Plants and the human body have a lot in common. Among other
characteristics, both need basic nutrients to keep them going.

Plants need three major and ten minor nutrients for healthy growth.

Nitrogen

Nitrogen (N) is essential for growing strong vegetables. Nitrate is the
form most readily absorbed by plants and most desirable as a fertilizer.

Leafy vegetables, such as spinach, cabbage, kale and lettuce,
especially benefit from fertilizers with a high nitrogen content. Nitrogen-deficient
plants display leaves that yellow from their tips toward the stem. Excessive nitrogen
creates weak spindly growth, resulting in few flowers and fruits.

Nitrogen can be lost in the soil by the leaching action of irrigation
and rainfall. Legumes, such as clover, "fix" nitrogen into the soil, making them
excellent additions to any garden.

Phosphorus

Phosphorus is important to early root growth, cell division and
respiration. It's also necessary for fruit production. Phosphorus doesn't dissolve and
move through the soil. The root tips absorb whatever phosphorus that is available, so it
must be placed as near to the roots as possible to be accessible to the plant. Tuber and
root crops, such as potatoes and carrots, benefit from phosphorus applications. Watch for
stunted growth, dead older leaves or red or purple leaves and stems. These symptoms may
suggest a need for more phosphorus.

Potassium

Potassium affects photosynthesis, fruit formation and winter hardiness.
Place potash near the roots in the form of humus to improve the general well-being of
plants deficient in potassium. Watch for yellowed leaves or susceptibility to disease that
may indicate the need for potassium nutrients such as muriate or sulfate of potash.

Calcium, Magnesium and Sulfur

Of the minor nutrients needed by our gardens, calcium magnesium and
sulfur generally are sufficient in our area soils. These are important in the growth and
manufacture of chlorophyll. Many of the other minor nutrients found in fertilizers
actually act as catalysts for the plant to utilize or break down other food available to
it.

Fertilizer Formulations

Fertilizer comes in many formulations. The three numbers on all
fertilizer containers stand for nitrogen-phosphorus-potash. Apply fertilizer 2 to 3 inches
from the plant when applying at planting time. Failure to fruit and injury may result from
too much fertilizer. Exercise caution when applying dry fertilizer granules. They are
worked into the soil surface and dissolved with water, but they can easily burn the plant
if used improperly. Liquid fertilizer may be preferable because nutrients are made
available to the plant immediately.

Simple fertilizer, such as 0-46-0, contains only one of the three major
nutrients. Complete fertilizers, such as 15-30-15, for example, contain portions of all
three major nutrients. You also will find special purpose fertilizers available, such as
rose or tomato food. And, you might want to try some of the many sticks, stakes and tablet
forms of fertilizer on the market. These are compressed fertilizers that dissolve slowly
as you water and yield nutrients gradually.

If you want a more natural approach, try organic fertilizers, such as
bone or blood meal, manure or cottonseed meal. These are derived from the remains or
by-products of once-living organisms.

Whatever method you choose, keep in mind that vegetables generally are
fast-feeders. You will find tomatoes, broccoli, cabbage and celery to be among the
heaviest while eggplant, horseradish and herb salsify are among the lightest. Many of our
most popular garden vegetables, such as carrots, beets, garlic, onions, squash, peppers
and potatoes, are medium feeders and will fall somewhere in between the two. Read the
product directions carefully and pay close attention to the results of the products you
try. Keep a record of uses and results.